Electrolytic process and product



- M. M. MERRITT.

ELECTROLYTIC PROCESS AND PRODUCT. TION Fl ED NOV 2 1917 RENEW D n APPLICA L V 4,1919. 1,335,846, Patented Apr. 6, 1920.

Inventor MaZthewM.Merrj/i7i.

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urn ED TA-gas P ENT oErIoE- MATTHEW M. MERnrTT; or SOUTH MIDDLETON, MASSACHUSETTS, ASSIGNOR To COPPER PRODUCTS co r'ANY, or nosTon, MASSACHUSETTS, A conroEATIoN or MAINE.

/ ELECTROLYTIC rnooEss AND rnoDUcT.

v Application filed November 2, 191'7, Serial No. 199,808; Renewed December 4, 1919. Serial No. 842,477.

To all whom it may concern:

Be it known that I, MATTHEW M. MERRrrr,

a citizen of the United States, and a resident of South Middleton, county of Essex, Com- 5 monwealth" of Massachusetts, have invented-g w an Improvement in Electrolytic Processes and Products, (A,) of which the following description, in connection with the. accom panying drawings, is a specification, like characters on the drawings representing like parts. i

This invention pertains to improvements in'electrolytic processes and products, and more particularly, though not exclusively,

to improvements in the art of electrolytically depositing copper or other metal on the surfaces of non-conductive bodies such as bodies composed of wood. p

The invention is'peculiarly useful as ap- 2p plied to electrolytically coating with copper the surface of aeroplane propellers;

In the drawings that show one form of an illustrative embodiment of my invention:

coated with copper;

Fig. 2 is adiagrammatic section therethrough on the line 22 of Fig. l,

I have found that when an aeroplane propeller is coated with an electrically conducdeposits of copper are made thereon, that thestructure of the deposited copper is relatively coarse. and the sheet of copper comparatively brittle. I believe this to be due to the comparatively coarse structure of the bronze powder, there being a tendency for 40 the deposited copper to partake of thegeneral structure, so'far as coarseness is concerned, of the electrically conductive body -on which it is deposited. The life of the copper coating on an aeroplane propeller depends on its toughness and fineness of structure. I have found that a verytough coating of electrolytically. deposited copper may be deposited by initially depositing on the electrically conductive paint or the like,

- a layer of copper, preferably'comparatively thin, amalgamating this copper Surface with 'mercury or with a mercury amalgam, and then depositing onthe amalgam surface a second layer or lamination of copper. I

The second layer of copper is of very Specification of Letters Patent.

Figure 1 shows anaeroplane propeller" Patented Apr. 6, 1920,

fine-grained, close texture because the initially coarse first copper coating has been rendered fine-grained by the application of the mercury or mercury amalgam.

It is incontrovertible that the application weakeningof the copper structure is prob ably due to the penetration of the mercury between the pores of the copper with resultant reduction of the cohesion of the copper.

'of mercur or mercury amalgam to a copper In making the experiments leading up to the present invention, I had expected that the'first sheet of copper would be so weakened by the mercury that it would contribute practically no strength to the tructure. I

found, however. on stripping a blade made I irt accordance with the present invention,

that the deleterious effect of the mercury on the initial. copper coating appears to be corrected'or, in any case, greatly reduced by the combined action of the electrolyte" and the current during the subsequent electrodeposition, leaving the initial coating of copper very ductileand strong. The effect I of the mercury between the .first and second coating is to laminate thestructure and I may, ifdesired, continue the laminations by amalgamatingthe surface of the deposited metal several times, thus producing a copper reinforcement for the propeller having any desired number of 'lam'inatio'ns.

.In my co-pending application, filed herewith, I have described the use of grease in variou waysto produce fineness of texture 'of the successive copper deposits and, if desired, to effect laminations therein. It will be understood that the present invention,

and that described in my co-pending appli-' cation, may be used in conjunction with one another or alternatively, thegeneric dominating claims being included in this application.

I have founditof marked advantage to rotate the cathode during the electro-deposition and, in the case of aeroplane propellers, it is highly desirable that the directhat the excess of copper which necessarily ,tion of rotation be intermittently reversed so v becomes deposited on the advance edges of v the blades during rotation will be more evenly distributed betweem the opposite edges of the blades. r

While rotation coupled with complete im- "1918, Serial No. 254,633, filed September 18,

thereon while rotating the partial submergence in the e ectrolyte. 1 The niersion is of advantagejl prefer to immerse only about one-half the propeller, locating the axis about which the propeller is revolvedat or near the surface of the electrolyte The propellers manufactured with partial submergence, as before described, are

considerably smootherand finer grained on the surface than propellers coated in a 'still bath or under agitation coupled with complete submergence or substantially; complete. submergence.

The claims of the present application are limited to coating propellers by the application of an electrically conductive paint, and then electrolytically depositing metal ropeller under carrying on of electro-deposition in which the cathode is alternately immersed and emersed in the electrolyte is claimed broadly in various formsin my copending applications,- Serial No. 247,967, filed August2,

1918, Serial No. 247,966, filed August 2,

' 1918,3114 Serial No} 247,964, filed August 2',

While I have "s ow I embodiment of my invention, it will be understood thatfImay greatly vary the same without departing from the scope of my invention, which is best 'defined in the' ifolo submergence in anielectrolytex' 1 2. The meth'odjof coating an aeroplane propeller which comprises coating the pro-1 peller with an electricallyconductive paint,.-

and electrolytically; depositing metal there-v on while rotating thepropeller under partial I 'gfthe propeller under partial submergence in an electrolyte; the direction of rotation being periodically reversedi 1 In testimony whereof I have signed my name to this specification. y MATTHEW Mi 'MERRITT." 1 

